How T Rex pulverised its prey with the bite force of three small cars

TYRANNOSAURUS Rex had a bite with the force equivalent to the weight of three Ford Fiestas, a study has found.

The predator, which roamed the earth around 65 million years ago, was thought to have had the largest bite force of any land animal but it was not known exactly how strong its jaws were. Now US researchers have found T Rex’s jaw exerted 3.6 tons of force, equivalent to the weight of three midsized cars, more than twice the bite force of today’s largest living crocodile.

The dinosaur’s tooth pressure – a new metric devised by the researchers – was even greater: 30 tons per sq cm (195 tons per square inch) of dental surface. T Rex could not only crack the biggest of bones, it could also pulverise and ingest them, absorbing marrow and minerals beyond the reach of its lesser competitors.

“The combination of impressive bite force and stout teeth set T Rex apart,” said lead author Paul Gignac, an assistant professor at Oklahoma State University. “It regularly scored, deeply punctured and sliced through bones.”

The study, by Prof Gignac and Gregory Erickson from Florida State University, built on research examining modern crocodiles, analysing the muscles that contribute to their bite force. They devised a model for T Rex’s bite after comparing the findings with birds, which evolved from the same group of dinosaurs as T Rex. The research added comparisons with modern wolves and hyenas which are also able to crush bones with their teeth to access nutritious marrow. They have so-called occluding teeth that fit together perfectly, top and bottom, a feature common in carnivorous mammals. But T Rex lacked such teeth, raising the question of how it managed to shatter resistant bones the size of small tree trunks.

Prof Gignac said the difference was that T Rex had “extraordinarily large, conical and strongly rooted teeth that were replaced after being worn every couple of years”. The findings are reported in the journal Scientific Reports.